1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Non-trivial C macros cannot be used in Rust. Similarly, inlined C functions 4 * cannot be called either. This file explicitly creates functions ("helpers") 5 * that wrap those so that they can be called from Rust. 6 * 7 * Even though Rust kernel modules should never use directly the bindings, some 8 * of these helpers need to be exported because Rust generics and inlined 9 * functions may not get their code generated in the crate where they are 10 * defined. Other helpers, called from non-inline functions, may not be 11 * exported, in principle. However, in general, the Rust compiler does not 12 * guarantee codegen will be performed for a non-inline function either. 13 * Therefore, this file exports all the helpers. In the future, this may be 14 * revisited to reduce the number of exports after the compiler is informed 15 * about the places codegen is required. 16 * 17 * All symbols are exported as GPL-only to guarantee no GPL-only feature is 18 * accidentally exposed. 19 */ 20 21 #include <linux/bug.h> 22 #include <linux/build_bug.h> 23 #include <linux/err.h> 24 #include <linux/refcount.h> 25 #include <linux/mutex.h> 26 #include <linux/spinlock.h> 27 #include <linux/sched/signal.h> 28 29 __noreturn void rust_helper_BUG(void) 30 { 31 BUG(); 32 } 33 EXPORT_SYMBOL_GPL(rust_helper_BUG); 34 35 void rust_helper_mutex_lock(struct mutex *lock) 36 { 37 mutex_lock(lock); 38 } 39 EXPORT_SYMBOL_GPL(rust_helper_mutex_lock); 40 41 void rust_helper___spin_lock_init(spinlock_t *lock, const char *name, 42 struct lock_class_key *key) 43 { 44 #ifdef CONFIG_DEBUG_SPINLOCK 45 __raw_spin_lock_init(spinlock_check(lock), name, key, LD_WAIT_CONFIG); 46 #else 47 spin_lock_init(lock); 48 #endif 49 } 50 EXPORT_SYMBOL_GPL(rust_helper___spin_lock_init); 51 52 void rust_helper_spin_lock(spinlock_t *lock) 53 { 54 spin_lock(lock); 55 } 56 EXPORT_SYMBOL_GPL(rust_helper_spin_lock); 57 58 void rust_helper_spin_unlock(spinlock_t *lock) 59 { 60 spin_unlock(lock); 61 } 62 EXPORT_SYMBOL_GPL(rust_helper_spin_unlock); 63 64 int rust_helper_signal_pending(struct task_struct *t) 65 { 66 return signal_pending(t); 67 } 68 EXPORT_SYMBOL_GPL(rust_helper_signal_pending); 69 70 refcount_t rust_helper_REFCOUNT_INIT(int n) 71 { 72 return (refcount_t)REFCOUNT_INIT(n); 73 } 74 EXPORT_SYMBOL_GPL(rust_helper_REFCOUNT_INIT); 75 76 void rust_helper_refcount_inc(refcount_t *r) 77 { 78 refcount_inc(r); 79 } 80 EXPORT_SYMBOL_GPL(rust_helper_refcount_inc); 81 82 bool rust_helper_refcount_dec_and_test(refcount_t *r) 83 { 84 return refcount_dec_and_test(r); 85 } 86 EXPORT_SYMBOL_GPL(rust_helper_refcount_dec_and_test); 87 88 __force void *rust_helper_ERR_PTR(long err) 89 { 90 return ERR_PTR(err); 91 } 92 EXPORT_SYMBOL_GPL(rust_helper_ERR_PTR); 93 94 bool rust_helper_IS_ERR(__force const void *ptr) 95 { 96 return IS_ERR(ptr); 97 } 98 EXPORT_SYMBOL_GPL(rust_helper_IS_ERR); 99 100 long rust_helper_PTR_ERR(__force const void *ptr) 101 { 102 return PTR_ERR(ptr); 103 } 104 EXPORT_SYMBOL_GPL(rust_helper_PTR_ERR); 105 106 struct task_struct *rust_helper_get_current(void) 107 { 108 return current; 109 } 110 EXPORT_SYMBOL_GPL(rust_helper_get_current); 111 112 void rust_helper_get_task_struct(struct task_struct *t) 113 { 114 get_task_struct(t); 115 } 116 EXPORT_SYMBOL_GPL(rust_helper_get_task_struct); 117 118 void rust_helper_put_task_struct(struct task_struct *t) 119 { 120 put_task_struct(t); 121 } 122 EXPORT_SYMBOL_GPL(rust_helper_put_task_struct); 123 124 /* 125 * We use `bindgen`'s `--size_t-is-usize` option to bind the C `size_t` type 126 * as the Rust `usize` type, so we can use it in contexts where Rust 127 * expects a `usize` like slice (array) indices. `usize` is defined to be 128 * the same as C's `uintptr_t` type (can hold any pointer) but not 129 * necessarily the same as `size_t` (can hold the size of any single 130 * object). Most modern platforms use the same concrete integer type for 131 * both of them, but in case we find ourselves on a platform where 132 * that's not true, fail early instead of risking ABI or 133 * integer-overflow issues. 134 * 135 * If your platform fails this assertion, it means that you are in 136 * danger of integer-overflow bugs (even if you attempt to remove 137 * `--size_t-is-usize`). It may be easiest to change the kernel ABI on 138 * your platform such that `size_t` matches `uintptr_t` (i.e., to increase 139 * `size_t`, because `uintptr_t` has to be at least as big as `size_t`). 140 */ 141 static_assert( 142 sizeof(size_t) == sizeof(uintptr_t) && 143 __alignof__(size_t) == __alignof__(uintptr_t), 144 "Rust code expects C `size_t` to match Rust `usize`" 145 ); 146